Verification and validation technologies for gas dynamic simulations

Abstract

This paper presents a review of the literature on terminology, methodology and technology of verification and validation processes related to the field of computational gas dynamics. The interdisciplinarity of the used approaches that are developed by the efforts of specialists in various branches of knowledge such as operations research, statistical analysis, and computational physics is highlighted. Such fundamental problems as comprehension of the verification procedure features for computational code and solution; comprehension of the validation process specificity for model and computational solution, identification of sources of errors and uncertainty, definition of the role of validation in predictive modeling are discussed. The basic principles of the validation based on identification and quantification of errors in the computer simulation model and numerical solutions obtained using this model are formulated. Particular attention is paid to methods for estimating the accuracy of calculations. The importance of computational software testing in the framework of verification is highlighted. The validation strategy that involves a hierarchical representation of the complex interrelated physical processes occurring in the simulated engineering system is described. Approaches to planning and conducting validation experiments are presented. Methods for estimating the experimental error, random and systematic errors are described. The necessity of using nondeterministic calculations in the validation activity to take into account the factor of experimental uncertainties in the numerical simulation process is substantiated. Some examples of the application of the described methods are given. Verification and validation of a two-dimensional model for inviscid perfect compressible medium are performed. This model occupies the lower level in the hierarchy of integrated models of complex physicochemical processes which are developed in IPMech RAS for solving coupled problems of thermogasdynamics.